Genome-wide association studies (GWAS) are commonly used to identify common single nucleotide polymorphisms (SNPs) that influence human traits. GWAS have been conducted at increasing frequency using case-control, population-based prospective, and cross-sectional study designs [1-6]. More recently, GWAS are being conducted in cohorts that are clinic-based [7-10]. As a result, GWAS may soon move the field of genomics into clinical practice.
